• Proceedings of the KWS Conference
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• 2009.11a
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• pp.57-57
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• 2009

산업의 고도화에 따른 구조물의 사용 환경이 열악해지고 최근 에너지저감과 환경문제 개선을 위한 경화의 요구에 따라 뛰어난 내식성 및 우수한 고비강도 특성을 갖고 있는 타이타늄 및 타이타늄합금의 활용에 대한 연구가 많은 주목을 받고 있다. 이에 따라 타이타늄 신합금의 개발뿐만 아니라 기존에 개발되어 비교적 보편적으로 적용되고 있는 타이타늄 부품의 제조 및 성형기술에 대한 수요도 급증하고 있다. 특히, 기기 및 부품 제조를 위한 용접/접합기술도 매우 중요한 요소기술로 자리메김하고 있다. 타이타늄은 산소, 수소 등의 침입형 원소와의 친화력이 강한 활성이 큰 금속으로 용접시 고온에 노출되면 급격히 산화 및 취화 등의 문제를 발생한다. 따라서 타이타늄의 용접시에는 $426^{\circ}C$이상의 온도에서는 대기로부터 용접부가 차단되도록 하는 쉴딩기술이 매우 중요하다. 타이타늄의 용접은 일반적으로 아크용접, 전자빔 용접, 레이저 용접 및 확산접합 등이 적용되고 있으나 용접입열 조정이 용이하고 아크 안정성이 높고 용접부의 기계적 특성이 우수한 GTA 용접이 작업성을 고려하여 가장 많이 적용되고 있다. 본 연구에서는 미국용접학회(AWS)의 타이타늄 용접가이드를 분석 및 소개하였고, 1t 이하의 박판 CP Ti를 대상으로 GTAW 용접부 미세조직 및 기계적 특성을 분석하였다. 이때, 용접 비드폭 제어 및 펄스 용접기술을 통하여 박판 타이타늄의 최적 GTAW 공정변수 제어기술을 분석하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.518-521
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• 2005

We performed the mechanical test for obtaining properties of femoral head. Tested sample was male and 35 years old. We measured bone mineral density by dual X-ray absorption method(DEXA). Results of DEXA, he has normal condition of bone density. His BMD $1.159g/cm^2$ and T-Score is 1.6. Tested femurs were harvested by surgical method from donated cadaver. We made 9 specimens in femoral head, 8 specimens in neck used by diamond core drill. Then we performed compressive test in saline solution at $38^{\circ}C$. We obtained results that elastic modulus of femoral head was 0.439GPa, neck was 0.459GPa. Compressive strength of femoral head was 7.441 MPa, neck was 7.095MPa. There was no significant difference of mechanical properties between left and right femoral head & neck. Invested local properties of femoral head have more strength superior and anterior side, femoral neck has more strength in superior and inferior side but other side except for superior has more weakness along the lateral side.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.502-509
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• 2011

It is important to determine optimum soil covering depths for tree survival and growth because soil covering depths for establishing tree planting bases in coastal reclaimed lands are related to the costs for soil collection, transportation and land reclamation. The objectives of this study were carried out to determine optimum soil covering depths for the normal growth of planted trees in a coastal reclaimed land. The study sites were located in Asan National Industrial Complex in Pyeongtaek City, Gyeonggi-do. Four tree species (Pinus thunbergii, Chamaecyparis pisifera, Zelkova serrata, Quercus acutissima) with one hundred eighty trees of each species were planted in various depths of soil covering (no soil covering, 0.5 m, 1.5 m, 2.0 m soil covering treatments) on April 1998, and the tree growth patterns were measured on September 2000. The change of soil properties, tree mortality rate, root collar diameter and height growth were measured from each soil covering depth treatment on September 2000. Soil pH, EC, exchangeable cations ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$), anion $Cl^-$, and base saturation increased with decreased soil covering depths. The mortality rates of tree species showed decreased with increased soil covering depths. The height growth of tree species increased with increased soil covering depths. Height growth of Pinus thunbergii was significantly different between the soil covering depth below 0.5m and other three covering depths, while the growth of other species (C. pisifera, Z. serrata, Q. acutissima) was significantly higher in soil covering depths below 1.5 m than in other soil covering depth treatments. The root collar diameter growth of all tree species showed increasing trends with increased soil covering depths. It is recommended to cover the soil depths above 1.5 m to decrease mortality and to stimulate the tree growth of C. pisifera, Z. serrata and Q. acutissima, while P. thunbergii which is a salt tolerate species could be planted in the 1.0 m soil covering depth.

• Resources Recycling
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• v.26 no.6
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• pp.29-37
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• 2017

Nuclear fuel cladding tube is fabricated by pilgering and annealing process. In order to remove impurity and oxygen layer on the surface, pickling process is carried out. When Zirconium(Zr) is dissolved and saturated in acid solution during the pickling process, all the waste acid including Zr is disposed. Therefore, $BaF_2$ is added into the waste acid to extract Zr and $Ba_2ZrF_8$ is subsequently formed. To recycle Zr by electrowinning process, $Ba_2ZrF_8$ is used as electrolyte, but it has high melting point ($1053^{\circ}C$). $ZrF_4$ should be added into $Ba_2ZrF_8$ to decrease the melting point. In this paper, it was investigated that $Ba_2ZrF_8$ was separated to $BaF_2$ and $ZrF_4$ by vacuum distillation. Firstly, $BaF_2$ with different particle size ($1{\mu}m$, $35{\mu}m$, $110{\mu}m$) was added into the waste acid and the respective precipitation property was estimated. $BaF_2$ obtained by vacuum distillation was shattered by ball-milling with different time. The precipitation efficiency was compared with $1{\mu}m$ of ${BaF_2}^{\prime}s$ one, which was not used as precipitation agent.

• Journal of Digital Contents Society
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• v.9 no.2
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• pp.285-293
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• 2008

In Semantic Web, metadata and ontology for representing semantics and conceptual relationships of information resources are essential factors. RDF and RDF Schema are W3C standard models for describing metadata and ontology. Therefore, many studies to store and retrieve RDF and RDF Schema documents are required. In this paper, we focus on some results of analyzing available query patterns considering both RDF and RDF Schema and classify queries on RDF and RDF Schema into the three patterns. RDF and RDF Schema can be represented as graph models. So, we proposed some strategies to store and retrieve using the graph models of RDF and RDF Schema. We can retrieve entities that can be arrived from a certain class or property in RDF and RDF Schema without a loss of performance on account of multiple joins with tables.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.310-310
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• 2010

ZnO 바리스터는 정전기 (ESD) 및 순간적인 써지(surge)로부터 전자기기 및 전자회로 등을 보호하기 위해 개발된 전자 세라믹스 소재이다. 최근 전자기기 등의 고속통신 추세에 따라 ZnO 바리스터는 높은 비선형 특성과 함께 보다 낮은 유전율 및 유전손실 특성이 특별히 요구되고 있다. 본 연구에서는 현재 양산되고 있는 Bi-계와 Pr-계 ZnO 바리스터가 아닌 새로운 조성계에 $Mn_3O_4$를 0.0~3.0 at% 첨가하여 소결 및 전기적 특성들 살펴보았다. 시편은 일반적인 세라믹 공정에 따라 제조하여 $1200^{\circ}C$에서 1 시간 공기 중에서 소결하였으며, 소결 및 전기적 특성과 유전 특성(밀도, 미세구조, I-V 특성, 유전율, 유전손실, ZnO 비저항)은 FE-SEM, Keithley237, Agilent 4294a 및 Agilent 4991a 장비를 사용하여 첨가제에 따른 ZnO 바리스터의 특성 변화를 관찰하였다. 그 결과 Mn이 0.2 at% 첨가한 계의 바리스터의 상대밀도는 95%, 비선형계수는 14, 유전율은 140 (at 1MHz), 손실값은 0.147 (at 1 MHz)를 나타내었다. 이를 통하여 새로운 바리스터 조성계에서 Mn의 첨가에 따른 효과에 대하여 논하였다.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1332-1338
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• 2003

This study was undertaken to examine the influence of soluble non-starch polysaccharides on growth performance, mucin secretion, and endogenous amino acid flows in weaner pigs. Different levels (0, 4 and 7.5%) of purified corn arabinoxylan (AX) or barley $\beta$-glucan extract (BG) were substituted for cellulose in a purified diet based on starch, sucrose and enzymatically hydrolyzed casein. All diets contained titanium oxide as an indigestible marker. Each experimental diet was fed to five, 6-wk old weaner pigs for 21 days. Average daily gain (p<0.05) and feed conversion ratio (p<0.01) were improved with dietary inclusion of 7.5% AX and BG, indicating high degradation rates of AX and BG in pigs. Crude mucin contents and endogenous nitrogen flow were increased (p<0.05) with increased levels of AX, but not with BG. Numerical increases in endogenous amino acid flow (EAAF) were observed with increased levels of AX but no definite trend with BG. Endogenous amino acid flow in pigs fed mixed NSP diets (4% BG and 3.5% cellulose) was significantly higher (p<0.05) than those fed 7.5% BG diets. Among diets containing pure sources of soluble non-starch polysaccharides, endogenous amino acid flows were highest in 7.5% AX (p<0.05), intermediate in BG, and lowest in control diet. Increased flows (p<0.01) of threonine, proline and serine in pigs fed 7.5% AX diets are consistent with the increased flow of crude mucin determined in this treatment. In conclusion, mucin and endogenous amino acid flows were increased with dietary inclusion of AX, which could be related to its physicochemical property, particularly its high water-holding capacity. In contrast, $\beta$-glucan, due to its high degradation rate in pig, may be considered as unimportant factor in inducing mucin and endogenous amino acid secretions, at least at levels such as those used in this study.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1867-1869
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• 2003

In this paper, chamber(Circuit breaker compartment of C-GIS) made of stainless steel with 4 mm width is used. Artificial defect was made on enclosure or HV conductor of chamber and $SF_6$ gas was injected into it according to pressure. In this experiment, Acoustic emission sensors of different types was used to compare sensitivity to detect acoustic signal occurred by Partial discharge(PD) of according to types and resonance frequency in $SF_6$ gas atmosphere. Sensors used in tests was R6I, R15I and 2/4/6 Pre-Amplifier connected with R6IU without pre. amp. In case of R6IU, gain was adjusted with 40 dB like other sensors and operated by differential mode. Post amplifier(post. amp) and band pass filter(BPF) were developed Gain of post. amp. is 60 dB and BPF has band width of $50{\sim}300$ kHz. Also, envelope circuit developed reduces frequency of AE sensor. As a result, in $SF_6$ atmosphere, R6IU and R6I had resonance frequency of 60 Hz was better than R15I. Also, R6IU was better than R6I because of type property of pre.amp. had differential mode.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.5
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• pp.385-392
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• 2016

Recently in the display industry, demands for high-luminance and resolution of display devices have been steadily increasing. Generally, micro linear patterns are applied to an optical film in order to improve its properties of light. However, these patterns are easily viewed to eyes and moire phenomenon can be occurred. Micro random patterns are proposed as a method to solve these problems, increasing light-luminance and light-diffusion. However, conventional pattern manufacturing technologies have long processing times and high costs making it difficult to apply to large area molds. In order to combat this issue, micro-random patterns are formed by using a roll to plate indentation method along with abrasive paper tools composed of AlSiO2, SiC, and diamond grains. Also, forming properties, such as size and fill-factor of random patterns, are analyzed depending on type, mesh of abrasive paper tools, and indentation forces.

• Applied Microscopy
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• v.23 no.2
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• pp.53-77
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• 1993

In this study, an attempt was made to investigate the probable organelles participating in the secretion of biligrafin. The animals (ICR male mice, 25-30gm) were divided into normal control and 6 biligrafin injected groups to which 30% biligrafin (0.006ml/gm b.w.) were injected at 10, 20, 40, 80, 160 and 320 min prior to the sampling. The mice of each group were perfused through the heart with ice-cold 2.5% glutaraldehyde buffered with 0.1M Na-cacodylate (pH. 7.4) under the Na-pentobarbital (Nembtal 0.0015mg/gm b.w.) anesthesia and liver tissues were taken from each group. Some specimens were immersed 1 hr in the same solution used in the perfusion. After an overnight rinse in 0.1M Na-cacodylate buffer containing 10% DMSO and 7.6% sucrose, $75{\mu}m$ fronzen sections were made for cytochemical study. The sections were incubated in thiamin pyrophosphatase (TPPase) and inosine diphosphatase (ID Pase) media for 70 min at $37^{\circ}C$ respectively and acid phosphatase (AcPase) medium for 40 min at $37^{\circ}C$. They were postfixed in 1 % $OsO_4$ for 1 hr. The other specimens were immersed for 8 hrs in the fixative consisting of 2.5% glutaraldehyde and 3.0% paraformaldehyde buffered with Na-cacodylate (pH. 7.4). All of the osmificated specimens were processed for electron microscopy. In both normal and biligrafin injected groups, endoplasmic reticulum (ER), vacuoles, Golgi apparatus and lysosomes were seen in the vicinity of bile canaliculus. In the biligrafin injected groups, however, the Golgi apparatus appeared to be decreased and ER and vacuoles were dilated and increased. The rough endoplasmic reticulum (RER) having a few attached ribosomes appeared to be the round saccule, especially at 20 min after biligrafin injection. Smooth endoplasmic reticulum (SER) seemed to be formed by the detachment of ribosomes at the cisternal end of RER. The cistern of SER showed saccules which probably budded off to form the vacuole. The vacuoles were devoid of visible centents. This finding seemed to be in agreement with the biochemical property of the bile constituents. The fusion between the vacuoles and bile canaliculus were frequently seen in the groups injected with biligrafin. The lysosome did not show any changes in the biligrafin injected groups. Accumulation of some material and lipid droplets were seen at the 40 and 80 min after biligrafin injection, especially at the latter. At 160 and 320 min after biligrafin injections, however, they were decreased successively while the RER stack, free ribosomes and polysomes were increased. Although the reactive products of TPPase and IDPase were observed in the ER saccules and vesicles of the normal control and biligrafin injected groups, the fusion between the bile canaliculus and saccules or vesicles could easily be seen in the latter. The AcPase activity, however, was observed in the cistern at the maturing face of Golgi apparatus and lysosomes in both normal and biligrafin groups. The results suggest that the biligrafin is excreted via the vesicles, vacuoles or sacoules probably derived from the SER without the participation of Golgi apparatus and lysosomes, and the excess amount of material is stored as inclusions during the repairing of the organelles being overactive.